Answer:
(x -1)(12x +13)
Step-by-step explanation:
You are looking to rewrite the middle term as the sum of terms that have factors of (12)(-13) that have a total of +1. Those factors are -12 and +13, so the expression you are factoring by grouping is ...
12x^2 +13x -12x -13
= x(12x +13) -1(12x +13)
= (x -1)(12x +13)
